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This section describes key CloudPools concepts including:
SmartPools is the OneFS data-tiering framework, of which CloudPools is an extension. SmartPools alone tiers data between different node types within a PowerScale cluster. CloudPools also adds to tier data outside of a PowerScale cluster.
Although file data is moved to cloud storage, the files remain visible in OneFS. After file data has been archived to the cloud storage, the file is truncated to an 8 KB file. The 8 KB file is called a SmartLink file or stub file. Each SmartLink file contains a data cache and a map. The data cache is used to retain a portion of the file data locally, and the map points to all cloud objects.
The following figure shows the contents of a SmartLink file and the mapping to cloud objects.
Key options when configuring a file pool policy include:
CloudPools provides an option to encrypt data before the data is sent to the cloud storage. It uses the PowerScale key management module for data encryption and uses AES-256 as the encryption algorithm. The benefit of encryption is that only encrypted data is being sent over the network.
CloudPools provides an option to compress data before the data is sent to the cloud storage. It implements block-level compression using the zlib compression library. CloudPools does not compress data that is already compressed.
When files match a file pool policy, CloudPools moves the file data to the cloud storage. File-matching criteria enable defining a logical group of files as a file pool for CloudPools. The criteria define which data should be archived to cloud storage.
File matching criteria include:
Any number of file-matching criteria can be added to refine a file pool policy for CloudPools.
Caching is used to support local reading and writing of SmartLink files. It reduces bandwidth costs by eliminating repeated fetching of file data for repeated reads and writes to optimize performance.
Note: The data cache is used for temporarily caching file data from the cloud storage on PowerScale disk storage for files that have been moved off cluster by CloudPools.
The local data cache is always the authoritative source for data. CloudPools looks for data in the local data cache first. If the file being accessed is not in the local data cache, CloudPools fetches the data from the cloud. CloudPools writes the updated file data in the local cache first and periodically sends the updated file data to the cloud.
CloudPools provides the following configurable data cache settings:
Data retention is a concept used to determine how long to keep cloud objects on the cloud storage. There are three different retention periods:
Note: If more than one period applies to a file, the longest period is applied.